Pentax cameras underexposing.

I often read reviewers commenting, especially on the older models, that Pentax cameras underexpose. However I typically set my exposure to -2/3 and bracket it -2/3 to +2/3 thus getting three shots of -1 1/3, -2/3 and 0 and yet occasionally even with -1 1/3 I get blown out skies. So what do reviewers consider properly exposed, something that looks nice, but has the highlights blown out?

Perhaps it's just a lack of understanding on my part, but doesn't one buy a DSLR for best possible image quality and thus shouldn't highlight preservation be considered more important by reviewers than a shot that merely looks properly exposed at first glance, but has actually has destroyed a lot of highlight information?

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I'm critical because I care. I don't criticise things with no potential, so take it as a good sign.